1. Field of the Invention
The present invention relates to a scanner device, a scanner system and an image protection method for protecting the image data optically read by the scanner device.
2. Description of the Related Art
Document data the security of which is taken into consideration in various scenes are dealt with at the offices, the research institutes, or the like. For example, at the time of accessing the data of original image with high confidentiality, the matching of the password is required. At the time of printing the secret document, it is printed with a stamp of the mark indicating that the printed document is the secret document.
Security is taken into consideration at the stages of accessing and printing the secret document, in this way. However, in many cases, once the secret document is outputted, how to deal with the outputted document has not been settled.
For example, when the secret document is acquired with the scanner device, adding the viewing restriction or the access restriction to the acquired image data (electronic file) is not usually performed. Therefore, there is no substantial difference between the manner the acquired image data of a secret document is treated and the manner the acquired image data of a common document is treated.
On the other hand, there is the method of encrypting the electronic file that is proposed as the method of protection of the electronic file. For example, see Japanese Laid-Open Patent Application No. 2002-123767.
According to the method of Japanese Laid-Open Patent Application No. 2002-123767, the electronic file is encrypted, and the viewing of the encrypted electronic file by the third party can be inhibited. The personnel who is authorized to view the contents of this electronic file can acquire the key data that enables the encrypted electronic file to be decrypted, together with the electronic file. Therefore, the personnel can make use of the electronic file.
However, in the method of encrypting the electronic file of Japanese Laid-Open Patent Application No. 2002-123767, the key data is distributed to the user together with the electronic file, and there is the possibility that outflow or leakage of the key data occur with transmission of the electronic data. Therefore, it must be said that the level of protection of the electronic file of the secret document according to the method of Japanese Laid-Open Patent Application No. 2002-123767 is not adequately high.
Moreover, the user may encrypt the image data of the secret document acquired with the scanner device. However, if the method of encryption is not simple, it is difficult for many users to encrypt the acquired image data.